A novel mutation in the TSC2 gene protects against colorectal cancer in the Mexican population

Gac Med Mex. 2022;158(5):283-288. doi: 10.24875/GMM.M22000696.

Abstract

Introduction: Colorectal cancer (CRC) is a complex disease due to the large number of factors that influence its development, including variants in tumor suppressor genes.

Objective: To estimate allelic and genotypic frequencies of c.3915G>A and c.5371G>A variants of the TSC2 gene in a Mexican population with CRC, as well as to analyze their association with the development of CRC.

Methods: 126 peripheral blood samples from patients diagnosed with sporadic CRC and 134 from healthy individuals, regarded as the control group, were included. Identification of genotypes was carried out using traditional PCR and enzymatic digestion. All individuals signed an informed consent letter.

Results: The A allele of the c.3915G>A variant (OR = 0.31, 95% CI = 0.15-0.69, p = 0.004), as well as A/G haplotype of the c.3915G>A and c.5371G>A variants (OR = 0.28, 95% CI = 0.12-0.68, p = 0.005) showed a possible protective effect against sporadic CRC. In silico analysis indicated that both variants generate modifications in the splicing process.

Conclusion: The presence of TSC2 gene c.3915G>A variant suggests a possible protective effect against sporadic CRC in the Mexican population; however, no association was observed with the c.5371G>A variant.

Introducción: El cáncer colorrectal (CCR) es una enfermedad compleja debido al gran número de factores que influyen en su desarrollo, incluyendo variantes en genes supresores de tumores.

Objetivo: Estimar las frecuencias alélicas y genotípicas de las variantes c.3915G>A y c.5371G>A del gen TSC2 en una población mexicana con CCR, así como analizar la asociación con el desarrollo de CCR.

Métodos: Se incluyeron 126 muestras de sangre periférica de pacientes con diagnóstico de CCR esporádico y 134 de individuos sanos, considerados como grupo de control. La identificación de los genotipos se llevó a cabo mediante PCR tradicional y digestión enzimática. Todos los individuos firmaron una carta de consentimiento informado.

Resultados: El alelo A de la variante c.3915G>A (RM = 0.31, IC 95 % = 0.15-0.69, p = 0.004), así como el haplotipo A/G de las variantes c.3915G>A y c.5371G>A (RM = 0.28, IC 95 % = 0.12-0.68, p = 0.005) mostraron un posible efecto protector contra CCR esporádico. El análisis in silico indicó que ambas variantes generan modificaciones en el proceso de corte y empalme.

Conclusión: La presencia de la variante c.3915G>A del gen TSC2 sugiere un posible efecto protector contra CCR esporádico en población mexicana; sin embargo, no se observó esta asociación con la variante c.5371G>A.

Keywords: Colorectal cancer; Complejo esclerosis tuberosa 2; Cáncer colorrectal; Gen TSC2; Genes supresores de tumores; TSC2 gene; Tuberous sclerosis complex 2; Tumor suppressor genes.

MeSH terms

  • Colorectal Neoplasms* / genetics
  • Colorectal Neoplasms* / prevention & control
  • Humans
  • Mutation
  • Tuberous Sclerosis Complex 2 Protein* / genetics
  • Tumor Suppressor Proteins / genetics

Substances

  • Tuberous Sclerosis Complex 2 Protein
  • Tumor Suppressor Proteins
  • TSC2 protein, human

Supplementary concepts

  • Mexican people